1. Field of the Invention
The present invention relates to a body composition measuring apparatus for measuring the abdominal size of a human subject and for calculating an index of body composition based on the measured abdominal size.
2. Description of Related Art
Abdominal size has been widely used as an index for evaluating the physiques of humans. Abdominal size may be used as an index reflecting conditions of the trunk of the body, such as the amount of visceral fat. For example, if a person A and a person B were of the same height, if person A were to have a larger abdominal size, person A would have a higher degree of obesity, whereas if person B were to have a smaller abdominal size, person B would have a lower degree of obesity. For this reason, abdominal size is an index that is receiving attention as potentially helping people to avoid lifestyle-related diseases and adult-onset diseases so as to maintain good health.
There is disclosed, for example in Japanese Patent Application Laid-Open Publication No. 2002-85365, a device capable of obtaining a body composition index based on abdominal size and other parameters after receiving data on abdominal size that is manually input.
However, in a case in which a human subject or an operator inputs information regarding the abdominal size, such as waist circumference, the human subject or the operator does not always know the precise value of the waist circumference of the human subject, and therefore, the accuracy of the estimation of a body composition index tends to be unsatisfactory. In a case in which the waist circumference is input after it is measured, a tape measure or a band-type measure is often used. However, it is difficult and troublesome to position the tape measure or band-type measure at a desirable height horizontally all the way around the waist, for example, at the level of navel. Because the tape measure or band-type measure may often be misaligned, the values of the waist circumference in a series of measurements will be variable, i.e., the waist circumference cannot be measured in a reproducible manner.
There are other conventional body composition measuring apparatuses that are capable of estimating a body composition index without the abdominal size having to be input. However, indices such as fat ratio of the trunk portion, total fat area of the abdomen, abdominal subcutaneous fat thickness, abdominal muscle thickness, abdominal subcutaneous fat area, and visceral fat area in particular are highly correlated with abdominal size. Therefore, it is highly preferable to use abdominal size to more precisely estimate a body composition index. The abdominal size includes abdominal width (abdominal width in a lateral direction of the body of a human) and abdominal length (abdominal width in an anteroposterior direction of the body of a human) in addition to the above-described waist circumference.